Anti-Inflammatory Diet

All health care starts with diet. My recommendations for a healthy diet are here:
Anti-Inflammatory Diet and Lifestyle.
There are over 190 articles on diet, inflammation and disease on this blog
(find topics using search [upper left] or index [lower right]), and
more articles by Prof. Ayers on Suite101 .

Wednesday, June 29, 2011

Soluble Fiber: Food for Gut Flora

The human body only produces enzymes to digest proteins, fats, starch and a few simple sugars. The remaining components of food either pass through the intestines undigested (insoluble fiber) or are digested by bacteria and fungi in the colon (soluble fiber.) Soluble fiber feeds gut flora. Insoluble fiber is usually minimized by traditional food preparation, for example grains, because it contains unhealthy materials, such as phytic acid. Soluble fiber is healthy and required for normal development of the gut/immune system, whereas insoluble fiber should be avoided.

Soluble Fibers in Vegetables are Carbohydrates/Polysaccharides

Plant cells are surrounded by cell walls composed of long chains of sugars, polysaccharides. These wall polysaccharides, e.g. pectin, arabinogalactans, xyloglucans, and storage glucans and fructans, are highly complex in structure and can only be digested down to simple sugars by the action of dozens of different enzymes produced by dozens of different bacterial species in the colon. Many plants (as well as fungi and bacteria) also produce unique polysaccharides that are only susceptible to additional unique bacteria enzymes. Thus, digestion of diverse vegetables requires hundreds of different species of bacteria in the gut. Healthy gut flora consists of more than 150 different species of bacteria, which were eaten with food and adapt to the gut environment.

Food Intolerances/Most Food "Allergies"/Constipation Reveal Missing Enzymes

Enzymatic treatment of complex polysaccharides in the gut is a complex process that also yields many intermediate products that can influence both gut flora and the gut itself. A well adapted gut flora can systematically digest most of the food molecules that pass into the colon and produce only short chain fatty acids (CFAs) that feed the colon and pass through the liver to the rest of the body.

Antibiotics or a history of limited food choices and excessive hygiene can result in a simplified gut flora that only partially digests soluble fiber and results in accumulation of unusual byproducts that irritate the gut, and cause bloating and gas. Adverse reactions are called food intolerances or food allergies. Since bowel stools are composed predominantly of loosely packed gut flora, inability to fully digest and convert soluble fiber into more gut flora, also results in constipation.

Soluble Fiber in Meat is also Polysaccharide

Meat is made of fibers of protein connected to bone by polysaccharides. The tendons, gristle and other chewy parts of meat are made of chondroitin sulfate and other glycosaminoglycans (GAGs). Heparin is another GAG, which is released onto the surface of the intestines to block the adhesion of viruses and pathogens to the gut, and is subsequently digested by colon bacteria. Other components of meat (and vegetables), such as nucleic acids and some fats are also digested by enzymes of the gut flora. The versatility of gut flora to adapt to a huge variety of foods permits people to live on very diverse diets, ranging from vegan to paleo.

Modern Diets Starve and Simplify Gut Flora

Modern diets consist of processed foods that are made of fat, protein and starch, all of which are digested and absorbed before reaching the colon. These simplified foods produce a simplified gut flora that may also produce more CFAs rather than stool forming gut bacteria. In other words, eating larger amounts of simpler foods can result in more of the nutrients being absorbed and making it easier to gain weight on less food with a tendency toward constipation. These diets may also select for bacteria that maintain the simplified, "efficient" gut flora community and provide the potential for the spread of obesity through a population. Having friends and relatives who are obese and presumably have gut bacteria that favor obesity, increases the risk of obesity. It seems likely that obesity is contagious.

Simplified Gut Flora also Means a Compromised Immune System

Complexity in the gut flora is also needed to produce a healthy immune system, because different species of bacteria in the gut stimulate the development of different parts of the immune system, which develop in the lining of the gut. Soluble fiber is the normal food for the colon bacteria that control the part of the immune system that regulates autoimmunity and allergy, for example. Obesity is also associated with increased risk of degenerative and autoimmune diseases, which is consistent with defects in the gut flora that reside in the colon. Thus, the modern high carb diet contributes to the symptoms of obesity by elevating blood sugar, blood CFAs, as well as compromising the gut flora needed for normal functioning of the immune system.

Healthy Gut Flora = Anti-Inflammatory Diet + Eating New Bacteria

A damaged or simplified gut flora can be fixed by eating foods that supply nutrients for the body as well as feeding the gut flora, e.g. plenty of different types of soluble fiber. It is also necessary to eat the missing bacteria. Just adding a few probiotics with yogurt will not fix the problem and cooking kills all of the good bacteria. Fermented foods, especially those based on bacteria from your own home and garden, are good sources of health-providing bacteria. Raw vegetables will also provide bacteria that may be useful in your gut flora, as long as the vegetables are not too thoroughly washed. Sterilizing and cooking vegetables may avoid rare pathogens, but will certainly prevent contributions to a healthy gut flora.


Anonymous said...

Dr. Ayers,
I've been following your evolving guidelines and am experiencing definite improvements in my health and well being.
I seem to heal more quickly from cuts with minimal inflammation or infection. I assume this indicates my immune system is becoming more effective and having been antibiotic free for more than 5 years, I deduce that my gut flora is becoming more diverse and healthy.
My question is about adding new useful bacteria to the mix by eating diverse raw edible plants from the countryside. If I eat the odd dandelion leaf from different locations, would this permanently add the bacteria to the gut flora, or does there need to be constant replenishment?
I'm assuming that nibbling a variety of raw wild and pesticide/pollution free plants in the summer will be enough to maintain a healthy and diverse flora as long as I follow a rigorous anti inflammatory diet as you describe.
Also when eating new plants, are there any reactions I should expect? Such as flatulence, or perhaps loose stools as the gut adapts to and utilizes the new bacteria.

Gabriel said...

Which are good sources of new bacteria? I don´t have a garden and live in a big city. I eat fruit peel but wash it carefully as well as vegetables.

I eat yogurt but it seems it is not enough from your article and from experience. Should I add other fermented foods? Kombucha? Kefir?


John said...

Nice post--I know there have been several commenters in the past asking about meat/fat and gut bacteria.

Kristina said...


You can make sauerkraut, beet kvass, water kefir, coconut milk kefir, coconut water kefir, raw dairy kefir, and more all at home. Storebought yoghurt would not have many bacteria because it's heated and not fermented long enough.

Tomas said...

This looks like a decent source on fermentation:
and the book looks fine as well.

My latest attempt was making kefir as per Seth Roberts - very easy, convenient and tasty.

Anonymous said...

Dr Ayers, any thoughts on the role that viruses and fungus plays in the gut?

Are these essential to a healthy body as well?

Vincent said...

Dear Dr. Ayers,

As one who has terrible gut flora and chronic constipation, I am grateful for your posts on this topic.

I now eat an anti-inflammatory diet with fermented foods, but I do not have a garden or access to a lot of organic vegetables that I can eat unwashed. Under these circumstances, is it still advantageous to eat a wide variety of vegetables, or will doing so just aggravate my constipation and harm my gut by giving it types of soluble fiber it cannot handle?

I'd also welcome any other tips you may have for those of us without access to a lot of organic vegetables who want to improve our gut flora.

Whether or not you have time to respond, many thanks for your great work.

Anonymous said...

There is a chemical-free, vinegar-free Kimchi brand called Sunja's Kimchi -- available in mild or spicy -- that is quite good and effective for constipation. It's my go-to to increase bowel size and alleviate constipation. Plus it tastes great. It available on-line or I've bought mine at Whole Foods market too.

Do the fibers in raw nuts improve gut flora? I eat large amounts of raw hazelnuts and sometimes almonds (almonds too high in omega-6) -- they both keep me regular and I do not experience any digestestive distress. When available, I also enjoy raw macadamia nuts but sometimes they make my face flush -- niacin reaction?

Anonymous said...

I currently eat a pretty good diet following your guidelines, but I am wondering if I need something extra since I started off in such bad shape.

Do you think supplementation is a good route? I am thinking of adding pectin to my yogurt and taking lactulose.

Head of the Cave said...

Hey Dr. Ayers,

I have recently read this alarming article on the downsides of omega-3 fish oil supplementation

I would love to hear your opinion on this information

MikeH said...

Dr ayres,

I have been suffering for about 10 years with ulcerative colitis. I have had some success with an anti-inflammatory diet (scd) but have recently read about people who have all but cured themselves with high dose vitamin E enemas.

I have not come across you mentioning vit E before and I wondered what your take on this treatment was and if you did think it would help, what is the scientific reasoning behind this.

fantastically useful and informative blog. Thanks.

dogville said...

Could you please tell us about the role of diarrhea and low carb eating? Does it have to do with the high fat ingestion or are we allergic to dairy? Is it our bodies trying to adjust?

Anonymous said...

Was thinking that chia seeds may be a great food for the digestive tract. After soaking in water they balloon up and form a gel like substance.

Chia seeds are high in soluble fiber and are also high in Omega 3.

Anonymous said...

Dr. Ayers,

I was on off and on antibiotics for rosacea (doxycycline) for years -- literally. I've now been off for about 4 months and have been eating sauerkraut, kimchi, just started introducing kefir and low-sugar yogurt w/probiotics (Fage)... I generally eat a low-inflammatory diet, AND I take probiotics on top of that (ThreeLac and Udi's Choice).

My question is, how long should I expect it to take until my gut is healed? I know you can't give an exact estimate as everyone differs, but just curious as to whether it will take months or even years. Currently I'm not "regular" and still have rosacea/acne flareups.

Thanks so much!

Dean said...

Dear Dr. Ayers,

I need to pick your brain.

Can neurological symptoms like paresthesia and muscle twitching stem from gut flora dysbiosis?

How would you treat SIBO? Wouldn't inulin or pectin feed bacteria in the wrong places?

What does the excretion of bloody mucus 1-2 hours after ingestion of whey protein indicate?

Which parts of the GAPS diet do you agree and disagree with?

Thank you.

Katie13 said...

Dr. Ayers,

I found your discussion on soluble fiber and organic foods very interesting. I have a few questions though...
1. If the stomach is producing enough hydrochloric acid, wouldn't most bacteria (good and bad) be killed before entering the small intestine? I thought this was always the issue with buying probiotics that aren't guaranteed to make it through the stomach acid.
2. I thought the appendix produced and fed the "good bacteria" in the gut.
3. Have you read "The Pro-Vita Diet" by Dr. Jack Tipps? It is an excellent book that works with the body instead of against it (no proteins past 2pm, lots of veggies). He recommends washing everything in a hydrogen peroxide or bleach solution (very precise measurements) to form a sort of magnetic attraction to cleanse and "detox" foods before you eat them. This is all my interpretation, but I guess the negatively charged ions pull out and neutralize the positively charged toxins in the food. I do this and you can literally taste the difference - particularly in things like eggs, tomatoes, and celery. This solution would kill both good and bad bacteria.

Sarah said...

I have trouble with depression and recently found out I have mild diabetes. For a year I had lots of allergy symptoms and trouble sleeping before I went on a low carb diet. I stay away from omega 6 oils and eat butter, some coconut oil, and olive oil instead. If I eat the smallest amount of starch my allergy symptoms start to come back. Also, I have had smell hallucinations and smell distortions ever since being sick with a respiratory virus a year ago. It is thought that these things are caused by nerve damage. I wonder if the smell hallucinations are actually real, and that the source of these smells might be the gases I've read are given off by bad bacteria and/or fungus in the small intestine which go through the blood stream to the lungs to be expelled in the breath.

Asim said...

Dr. Ayers,

Great new article in the NY Times that speaks about microbiomes of the human, as it relates to cancer.

Would like your brief comments on it?

Asim said...

The latter portion parituclalry caught my eye:

"The composition of the microbiome changes not only geographically but also over time. With improved hygiene, dietary changes and the rising use of antibiotics, levels of the microbe Helicobacter pylori in the human gut have been decreasing in developing countries, and so has stomach cancer. At the same time, however, esophageal cancer has been increasing, leading to speculation that H. pylori provides some kind of protective effect."

Kate said...

Dr. Ayers,
I'm going to echo dean's question about SIBO. I have it, and have been advised that soluble fiber isn't exactly the greatest thing for me because it causes fermentation in the wrong place. What would you advise those of us with SIBO to do? It seems to be a fine balance between building a healthy population in the colon while avoiding overgrowth into the small intestine. What are your thoughts?

Dean said...

I now believe any FODMAPs to be very detrimental in SIBO. This includes inulin and even fructose (which is allowed in the GAPS diet in some forms). Bifidobacteria also need to be avoided, they might be part of the overgrowth and are fed by the aforementioned prebiotics.
In my case, SIBO and leaky gut seem to be responsible for inflammation, even TMJ and proteinuria. I read it's also suspected to cause rosacea.
Avoiding all FODMAPs and starch is helping, though it's neither an instant nor easy cure. I'm following a strict low carb high fat "autoimmune" paleo diet. My probiotics are L. Acidophilus and occasional raw lettuce and fermented foods.
Magnesium Peroxide (Ozovit) may also help. Taken over one week, it's supposed to release oxygen in the small intestine, clearing out pathogenic/anaerobe gut flora. I hope it isn't clearing beneficial flora too.
I'd appreciate hearing your thoughts about this, Dr. Ayers. If correct, I consider these implications substantial as concerns the cooling of inflammation.

Asim said...

Awesome article Dr. Ayers...

Conscious Life said...

Thanks for the informative post. We're only beginning to understand the many roles that gut flora play with respect to human health. And from the look of it, these microscopic inhabitants within us are far more important than we ever thought.

For those who wonder what are some good sources of probiotic foods that promote a healthy inflammation response, this article may be useful: Thanks.

Acu-Greg said...

Dr Ayers,

I had a thought I wanted to get your opinion on. To repopulate the gut with bacterial species, you often suggest fresh vegetables with soil still clinging to them. An idea/question came when I was hiking and was compelled to relieve some pressure in my colon. I often carry a little toilet paper in my backpack for such activities, but on that trip I had none. As I used some leaves gathered from the forest floor, I imagined that among cultures without toilet paper, that and similar methods would have been used regularly. I began to wonder if that might be a means of obtaining new species for the gut flora. Could bacteria be supplied to the colon via contact with the anus?

ironryan77 said...

Can you recommend a good book describing the anti-inflammatory diet?

Nicole said...

Dear Sir,
do you happen to know a doctor in Vienna who sees those inflammatory problems in a similar way to yours? It is some how critical. Thank you very much!

susan gutproblem said...

Dr Ayers
Can you help people who are intolerant to soluble fibre. I've been very thoroughly tested and there is no yeast/pathogenic bacteria/parasites in my gut. But also very few good bacteria - antibiotics last October and a course in oregano vulgare oil. i do hope you can help. Susan Coleman

Anonymous said...

Do you have any sources for your statement that dietary fiber is unhealthy? What i've been reading is just the opposite.

Dr. Art Ayers said...

Dietary fiber

The whole idea of fiber in the diet is deliberately confused by the food processing industry to cover up the fact that processing, which removes soluble fiber needed as a nutrient by gut bacteria, makes food unhealthy in order to promote food sales and make processed food more profitable.

So talking about food fiber is confusing.
Soluble fiber is essential for health to feed gut bacteria. Soluble fiber is prebiotic to feed gut bacteria that are probiotic.

Insoluble fiber is not digested by your enzymes or by enzymes of your gut bacteria. Whole grain flours are made by producing flour that lacks fiber (just starch and gluten and ATI) and adding back the insoluble fiber, which is an anti-nutrient that acts like an ion-exchange resin to remove dietary minerals. So whole grain flours are less nutritional than corresponding flours without the insoluble flour. Whole grain products are just a marketing ploy to sell anti-nutrients at an added price.

That said, there is a small amount of soluble fiber, plant polysaccharides that are needed to feed gut flora, that are added back with the insoluble bran and germ to reconstruct "whole grain" flours. That small amount of soluble fiber provides all of the small benefit of whole grain versus typical fours.

So, I say that fiber (plant polysaccharides other than glycemic starch) is good/essential for health, but insoluble fiber, e.g. lignin that carries phytate, is bad.

If you need references for basic nutrition, look up phytate/inositol hexaphosphate and lignin.

Thanks for your comments and please read my other 200 posts.

Scott Rao said...

Dr. Art,
I am a big fan of your blog and am grateful for all that you share.

I'm sorry this is a bit off-topic, but I have no idea where to post this, or how else to reach you. But I think you're one of the few people who might be able to answer my question.

I have multiple nematode infections that have been unresponsive to repeated courses of drugs. I recently read a passage in a book saying that sulphated carbohydrates could possibly expel strongyloides (one of my nematodes) binding the (worms') adhesion substances.

I'm wondering: what's the best way to increase the levels of GAGs in my intestines? Pop chondroitin sulphate pills? eat lots of seaweeds?

Thanks for your time.

Dr. Art Ayers said...

big bean,
Nematodes and GAGs: Of course the common GAGs in the gut are heparin and chondroitin. Heparin is produced by mast cells in the gut and coats the gut to prevent binding/infection by pathogens, including nematodes. Commercial heparin, one of the most common drugs used in hospitals, is produced by the guts of hogs and steers.

Another major source of a different type of sulfated polysaccharide is algae.

I don't know how to stimulate GAG production, but I think that chronic inflammation reduces heparan sulfate production involved in kidney and brain blood barriers. Thus, I would predict that your sensitivity to nematode infection reflects inadequate heparin production in the gut, which predicts chronic inflammation and associated vitamin D deficiency.

I would expect that correcting your vitamin D deficiency would be helpful. However, helminth infections suppress inflammation, which is a defense mechanism.

PEG is used to remove biofilms, so I would expect it to have an impact on intestinal nematodes, but I don't know what to predict.

Sorry to not be more helpful.

Let me know the outcome.

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